Three New Polycatenation Networks Based on 4,4′-Oxybis(benzoate) and Bis(imidazole) Ligands: Synthesis, Structure and Photoluminescence

In this paper we report three new metal-organic frameworks (MOFs), [Zn(oba)(L1)(0.5)(H2O)](n) (1), [Zn-2(oba)(2)(L-2)(2)](H2O)(3) (2) and [Co(oba)(L1)](n) (3) [oba = 4,4'-oxybis(benzoate), L1 = 1,4-bis(imidazol-1-ylmethyl)benzene, L2 = 1,4-bis(imidazol-1-yl) benzene] that have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and elemental analysis (EA). A structural investigation revealed that all three coordination compounds present polycatenation features. Interestingly, 1 shows a rare 1D -> 2D structure formed by the catenation of 1D ladders. Both 2 and 3, however, are unusual cases that have 3D frameworks constructed from 2D 4(4)-sql layers by parallel polycatenation. The photoluminescence properties of 1 and 2 have also been investigated.